This invention relates to a communication technique using sensor nodes. In particular, the invention relates to a technique of sharing confidential data and functions between a sensor node and a router, as well as protecting data in the sensor node.
Sensor nets in which many sensor nodes are connected through short-distance wireless communications have gained popularity in recent years. Using wireless communications to broadcast data, sensor nets contain such security risks as interception, tampering, and impersonation. Also, sensor nodes in sensor nets are often placed in unmanned sites, which gives rise to another set of problems including theft of data from a sensor node by physical means.
“Security Services Specification Revision 13, Version 1.00” (ZigBee Alliance, Dec. 14, 2004) proposes to use confidential data such as encryption keys given to sensor nodes in protecting wireless communications between sensor nodes against security risks.
In JP 2003-87242 A, JP 2004-318881 A, and JP 2004-241976 A, protection against security risks is accomplished by loading of confidential data and sensor node authentication performed by routers with the use of the confidential data.